n = gets.to_i

e10 = 10**10
sum = 0
n.times{|i|
    cin = gets.chomp!
    if /^-?\d+$/=~cin
       sum += cin.to_i*e10
    else
        t = cin.scan(/(-?)(\d+)\.(\d+)/)[0]
        k = t[1].to_i*e10 + t[2].to_i*10**(10-t[2].size)
        k = -k if t[0]=="-"
        sum += k
    end
}

if sum<0
    sum = -sum
    nu = sum/e10
    fr = sum%e10
    printf("-%d.%010d\n",nu,fr)
else
    nu = sum/e10
    fr = sum%e10
    printf("%d.%010d\n",nu,fr)
end